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`
`US 20040256468Al
`
`(19) United States
`(12) Patent Application Publication
`Akiho et al.
`
`(10) Pub. No.: US 2004/0256468 Al
`Dec. 23, 2004
`(43) Pub. Date:
`
`(54) ANTENNA DEVICE AND COMMUNICATION
`DEVICE USING ANTENNA DEVICE
`
`(76)
`
`Inventors: Hiraku Akiho, Miyagi (JP); Yutaka
`Okazaki, Tokyo (JP); Akihiro Kikuchi,
`Chiba (JP); Kazuo Goto, Kanagawa
`(JP); Kazuhiko Urayama, Tokyo (JP)
`
`Correspondence Address:
`WOLF GREENFIELD & SACKS, PC
`FEDERAL RESERVE PLAZA
`600 ATLANTIC AVENUE
`BOSTON, MA 02210-2211 (US)
`
`(21)
`
`Appl. No.:
`
`10/496,636
`
`(22)
`
`PCT Filed:
`
`Aug. 28, 2003
`
`(86)
`
`PCT No.:
`
`PCT/JP03/10985
`
`(30)
`
`Foreign Application Priority Data
`
`Sep. 25, 2002
`
`(JP) ......................................... 2002-27926
`
`Publication Classification
`
`Int. CI.7 .................................................... G06K 19/06
`(51)
`(52) U.S. Cl. .............................................................. 235/492
`
`(57)
`
`ABSTRACT
`
`An antenna device (60) is provided that is used in a recorder
`and/or writer destined for writing and reading data to and
`from a contactless IC card (1). The antenna device (60)
`includes a loop coil (61) that radiates a magnetic field,
`magnetically couples with a loop coil (4) provided in the IC
`card (1), and sends and receives data to and from the IC card
`(1). The loop coil (61) is formed asymmetric for the winding
`sections thereof opposite to each other across the center of
`the loop coil ( 61) to be different in interval from each other.
`
`102
`
`1 0 1
`
`IC
`
`100
`
`Petitioner Samsung and Google
`Ex-1022, 0001
`
`

`

`Patent Application Publication Dec. 23, 2004 Sheet 1 of 9
`
`US 2004/0256468 Al
`
`102
`
`1 0 1
`
`\
`
`IC
`
`100
`
`FIG.1
`
`--102
`
`----200
`
`r
`
`FIG.2
`
`Petitioner Samsung and Google
`Ex-1022, 0002
`
`

`

`Patent Application Publication Dec. 23, 2004 Sheet 2 of 9
`
`US 2004/0256468 Al
`
`>-
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`N
`
`N
`
`Petitioner Samsung and Google
`Ex-1022, 0003
`
`

`

`Patent Application Publication Dec. 23, 2004 Sheet 3 of 9
`
`US 2004/0256468 Al
`
`2.0
`
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`
`1 0
`
`30
`20
`POSITION (mm)
`
`4 0
`
`5 0
`
`FIG.4-
`
`Petitioner Samsung and Google
`Ex-1022, 0004
`
`

`

`Patent Application Publication Dec. 23, 2004 Sheet 4 of 9
`
`US 2004/0256468 Al
`
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`
`Petitioner Samsung and Google
`Ex-1022, 0005
`
`

`

`Patent Application Publication Dec. 23, 2004 Sheet 5 of 9
`
`US 2004/0256468 Al
`
`6 1 b
`
`r ...
`
`,
`
`.....
`
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`
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`z
`
`'
`
`60
`
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`J
`
`... ,
`
`[
`
`FIG_6
`
`Petitioner Samsung and Google
`Ex-1022, 0006
`
`

`

`Patent Application Publication Dec. 23, 2004 Sheet 6 of 9
`
`US 2004/0256468 Al
`
`N
`N
`
`X
`
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`
`Petitioner Samsung and Google
`Ex-1022, 0007
`
`

`

`Patent Application Publication Dec. 23, 2004 Sheet 7 of 9
`
`US 2004/0256468 Al
`
`60
`
`~
`
`z
`
`62
`I
`
`6 1 b -
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`
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`
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`(
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`
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`\
`
`)
`6 1 a
`
`FIG.9
`
`--- 6 1 d
`
`61c -
`
`I
`
`Petitioner Samsung and Google
`Ex-1022, 0008
`
`

`

`Patent Application Publication Dec. 23, 2004 Sheet 8 of 9
`
`US 2004/0256468 Al
`
`6 1 b
`(
`I
`
`6 2
`\
`
`----- 6 1 d
`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`00
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`000000 0
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`
`74
`
`z
`
`50
`FIG.1 1
`
`Petitioner Samsung and Google
`Ex-1022, 0009
`
`

`

`Patent Application Publication Dec. 23, 2004 Sheet 9 of 9
`
`US 2004/0256468 Al
`
`6 1 a
`
`6 1 b
`
`z
`
`FIG.1 2
`
`2.0
`
`---- 1.6
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`
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`
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`
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`
`1 0
`
`3 0
`2 0
`POSITION (mm)
`
`4 0
`
`5 0
`
`FIG.1 3
`
`Petitioner Samsung and Google
`Ex-1022, 0010
`
`

`

`US 2004/0256468 Al
`
`Dec. 23, 2004
`
`1
`
`ANTENNA DEVICE AND COMMUNICATION
`DEVICE USING ANTENNA DEVICE
`
`TECHNICAL FIELD
`
`[0001] The present invention relates to a reader/writer
`antenna device for writing and reading data to and from a
`contactless IC (integrated circuit) card adopting the tech(cid:173)
`nique of electromagnetic-inductive coupling and a commu(cid:173)
`nication device using the antenna device.
`[0002] This application claims the priority of the Japanese
`Patent Application No. 2002-279626 filed on Sep. 25, 2002,
`the entirety of which is incorporated by reference herein.
`
`BACKGROUND ART
`
`[0003] Recently, a so-called RFID (radio frequency iden(cid:173)
`tification) system using a contactless IC card, IC tag or the
`like has been introduced into the fields of art such as an
`automatic ticket checker used in the railway station, security
`system for checking people going to enter or exit from a
`building, electronic money system, etc. As schematically
`illustrated in FIG. 1, the RFID system includes a contactless
`IC card 100 and a reader/writer 101 to write and read data
`to and from the IC card 100. The RFID system adopts the
`theory of electromagnetic induction. An electromagnetic
`field radiated from a loop antenna 102 provided at the
`reader/writer 101 is coupled by the electromagnetic induc(cid:173)
`tion to a loop antenna 103 provided at the IC card 100 to
`provide communications between the IC card 100 and
`reader/writer 101.
`[0004]
`In the above RFID system, the IC card has not to
`be inserted into the reader/writer to put metallic contacts into
`contact with each other as in the conventional contactless IC
`card systems. Therefore, data can be written to, and read
`from, the IC card easily and quickly. Also, in the RFID
`system, the electromagnetic field radiated from the reader/
`writer 101 provides a necessary power to the IC card 100
`and thus any power source such as a battery or cell has not
`to be provided in the IC card. Therefore, the IC card used in
`the RFID system can be excellent in maintainability, lower
`in price and higher in reliability.
`[0005]
`In the above RFID system, the loop antenna 102
`provided at the reader/writer 101 should be able to radiate an
`electromagnetic field having a certain degree of magnetic
`strength in order to assure a satisfactory range of commu(cid:173)
`nications between the IC card 100 and reader/writer 101.
`[0006] Generally, the loop antenna 102 for the reader/
`writer 101 includes a loop coil 200 formed from a plane
`winding of a conductor as shown in FIG. 2. The loop coil
`200 is formed symmetric for winding sections thereof oppo(cid:173)
`site to each other across the center of the loop coil 200 to be
`equal in interval and width to each other.
`[0007]
`In the above symmetric loop antenna 102 for the
`reader/writer 101, the magnetic field is distributed sym(cid:173)
`metrically with respect to a Z-directional section through the
`center of the loop antenna 102, perpendicular to the long
`sides of the rectangular antenna and also to an X-directional
`section through that center, perpendicular to the short sides,
`as shown in FIG. 3.
`[0008] FIG. 4 shows the dependence upon the card posi(cid:173)
`tion of the strength of a current induced by the loop antenna
`
`102 to the IC card 100. As shown, two communication areas
`Si' and S2 ' are formed in positions, respectively, opposite to
`each other across the center of the loop coil 200. More
`particularly, the-communication area S1 ' assures an ideal
`magnetic coupling. Namely, magnetic fields developed at
`four sides of the loop antenna 102 at the reader/writer 101
`are inductively coupled to those developed at four sides of
`the loop antenna 103 at the IC card 100, opposite to the four
`sides, respectively, of the loop antenna 102. Outside the
`communication area S1 ', there is an area where magnetic
`fields crossing the loop antenna 103 at the reader/writer 101
`cancel each other in a central area where the magnetic fields
`developed around the loop antenna 102 at the reader/writer
`101 are inverted in direction. In this outer area, the induced
`current will have a lower level than the necessary level for
`the communications. Outside the above outer area, there is
`the communication area S2 ' where only one of the four sides
`of the loop antenna 102 at the reader/writer 101 is coupled
`to one of the four sides of the loop antenna 103 at the IC card
`100. Therefore, the communication area S2 ' is narrower than
`the communication area S1 ', and the induced current in this
`communication area S2 ' is smaller than that in the commu(cid:173)
`nication area S/
`[0009] Note that in FIG. 4, the origin "0" of the horizontal
`axis indicates the center of the loop antenna 102 at the
`reader/writer 101 and the positive-going direction indicates
`a direction from the center ( origin "0") toward outside of the
`IC card 100. The vertical axis indicates the strength of the
`current electromagnetically induced in the loop antenna 103
`at the IC card 100 under the action of the magnetic field in
`the loop antenna 102 at the reader/writer 101. Communica(cid:173)
`tions are possible in an area where the strength of the
`induced current has a value larger than a value indicated
`with a dashed line s' in FIG. 4.
`[0010] Note here that when the communication area S1 ' is
`continuously wider as far as possible outwardly of a point,
`namely, the origin "0", where the center of the loop antenna
`103 at the IC card 100 coincides with that of the loop
`antenna 102 at the reader/writer 101, the RFID system will
`be easier to use.
`[0011] That is to say, in a direction the origin "0" toward
`outside of the above conventional loop coil 200, the com(cid:173)
`munication area S1 ' is followed by a non-communication
`area once, and then by the communication area S2 '. It is
`desirable from the practical point of view that no non(cid:173)
`communication area should exist between the communica(cid:173)
`tion areas S 1 ' and S2 ' or only the communication area S 1 '
`should spread.
`
`DISCLOSURE OF THE INVENTION
`[0012] Accordingly, the present invention has an object to
`overcome the above-mentioned drawbacks of the related art
`by providing an improved and novel antenna device and a
`communication device using the antenna device.
`[0013] The present invention has another object to provide
`an antenna device used on a reader/writer and which can
`provides an expanded range of communications with an IC
`card by controlling, and effectively utilizing, the distribution
`of a radiated electromagnetic field, and a communication
`device using the antenna device.
`[0014] The above object can be attained by providing an
`antenna device that makes data communications with a
`
`Petitioner Samsung and Google
`Ex-1022, 0011
`
`

`

`US 2004/0256468 Al
`
`Dec. 23, 2004
`
`2
`
`contactless IC card by electromagnetic-inductive coupling,
`the device including according to the present invention:
`
`[0031] FIG. 3 shows the distribution of a magnetic field
`developed around the conventional R/W loop antenna.
`
`[0015] an asymmetric loop coil formed from a plane
`winding of a conductor, whose sections opposite to each
`other across the center of the loop coil are different in
`interval from each other; and
`
`[0016] a lead means for supplying a power to the loop coil.
`[0017]
`In the winding section in the above antenna device,
`of which the winding interval is larger than that in the
`opposite winding section, a wider range of communications
`with the IC card can be achieved.
`
`[0018] Also, the above loop antenna is smaller in plane
`area than a loop antenna included in the IC card.
`
`[0019] Also in the loop coil of the above antenna device,
`the winding interval should preferably be wider in a plurality
`of positions other than a first position.
`
`[0020] The loop coil is formed to have a generally square
`shape having four straight sides.
`
`[0021] Also, the above object can be attained by providing
`a communication device that makes data communications
`with a contactless IC card by electromagnetic inductive
`coupling, the device including according to the present
`invention:
`
`[0022] an antenna capable of electromagnetic inductive
`coupling with an antenna included in the contactless IC card;
`
`[0023] a modulating means for modulating send data to a
`predetermined carrier signal in order to communicate with
`the IC card with no contact with the antenna; and
`
`[0024] a demodulating means for demodulating receive
`data sent from the IC card electromagnetically coupled to
`the antenna.
`
`[0025] The antenna is disposed in a predetermined place
`on a housing of the communication device, in which it can
`be electromagnetically coupled to the contactless IC card.
`The antenna is a loop coil formed by winding a conductor
`like a loop generally in a plane for winding sections thereof
`opposed to each other across the center of the loop to be
`different in interval from each other.
`
`[0026] One of the winding sections of the loop coil, that is
`wider in winding interval than the other, is disposed near a
`position on a housing of the communication device where
`communications with the IC card is made.
`
`[0027] The communication device according
`present invention is of a hand-held type.
`
`to
`
`the
`
`[0028] These objects and other objects, features and
`advantages of the present invention will become more
`apparent from the following detailed description of the best
`mode for carrying out the present invention when taken in
`conjunction with the accompanying drawings.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0029] FIG. 1 is a perspective view of the conventional
`RFID system.
`
`[0030] FIG. 2 is a plan view of the conventional R/W
`(reader/writer) loop antenna.
`
`[0032] FIG. 4 shows a characteristic curve of a perfor(cid:173)
`mance of communications between the conventional R/W
`loop antenna and IC card.
`
`[0033] FIG. 5 is a circuit diagram of an RFID system
`according to the present invention.
`
`[0034] FIG. 6 is a plan view of the antenna device
`according to the present invention.
`
`[0035] FIGS. 7 A to 7C show characteristic curves, respec(cid:173)
`tively, of the distribution of magnetic field developed around
`the antenna device according to the present invention.
`
`[0036] FIG. 8 is a plan view of a variant of the antenna
`device according to the present invention.
`
`[0037] FIG. 9 is a plan view of another variant of the
`antenna device according to the present invention.
`
`[0038] FIG. 10 is a plan view of still another variant of the
`antenna device according to the present invention.
`
`[0039] FIG. 11 is a plan view of the communication
`device using the antenna device according to the present
`invention.
`
`[0040] FIG. 12 shows a characteristic curve of the distri(cid:173)
`bution of a magnetic field developed around the antenna
`device disposed in the communication device.
`
`[0041] FIG. 13 graphically illustrates, by induced current
`characteristic, the performance of communication of the
`antenna device according to the present invention with the
`IC card.
`
`BEST MODE FOR CARRYING OUT THE
`INVENTION
`
`[0042] The present invention will be described in detail
`concerning the antenna device and the communication
`device using the antenna device as the embodiments thereof
`with reference to the accompanying drawings.
`
`[0043] As shown in FIG. 5, the RFID system according to
`the present invention is composed of a contactless IC card 1,
`and a reader/writer (will be referred to as "R/W" hereunder)
`50 to write and read data to and from the IC card 1.
`
`[0044] The IC card 1 is of a battery-less type compliant
`with ISO 7810, for example. Namely, it has no power source
`such as a battery or cell. The IC card 1 is formed rectangular
`to have the same size as the so-called credit card, namely, it
`is palm-sized. The IC card 1 has provided on a circuit board
`built therein a loop antenna 2 that couples with an electro(cid:173)
`magnetic field to send and receive data, and an IC (inte(cid:173)
`grated circuit) 3 having integrated therein electronic circuits
`that make various operations for writing and reading data.
`
`[0045] The loop antenna 2 includes a loop coil 4 formed
`from a plane winding of a conductor, and forms a resonant
`circuit along with a capacitor 5 connected in parallel with the
`loop coil 4. The loop antenna 2 couples with an electromag(cid:173)
`netic field radiated from a loop antenna provided at an R/W
`50 that will be explained in detail later, converts the elec(cid:173)
`tromagnetic field into an electrical signal, and supplies the
`signal to the IC 3.
`
`Petitioner Samsung and Google
`Ex-1022, 0012
`
`

`

`US 2004/0256468 Al
`
`Dec. 23, 2004
`
`3
`
`[0046] The IC 3 includes a rectification circuit 6 to rectify
`and smooth the electrical signal supplied from the loop coil
`4, a regulator 7 to converter the electrical signal supplied
`from the rectification circuit 6 into a DC power, an HPF
`(high-pass filter) 8 to extract a high-frequency component
`from the electrical signal supplied from the rectification
`circuit 6, a demodulation circuit 9 to demodulate the high(cid:173)
`frequency component supplied from the HPF 8, a sequencer
`10 to control data write and read correspondingly to data
`supplied from the demodulation circuit 9, a memory 11 to
`store the data supplied from the demodulation circuit 9, and
`a modulation circuit 12 to modulate data to be sent by the
`loop coil 4.
`
`[0047] The rectification circuit 6 is composed of a diode
`13, resistor 14 and a capacitor 15. Of these parts, the diode
`13 is connected at the anode thereof to one end of each of
`the loop coil 4 and capacitor 5 and at the cathode to one end
`of the resistor 14 and capacitor 15, the resistor 14 and
`capacitor 15 are connected at the other ends thereof to the
`other ends of the loop coil 4 and capacitor 5. The rectifica(cid:173)
`tion circuit 6 outputs the electrical signal resulted by the
`rectification and smoothing the electrical signal supplied
`from the loop coil 4 to the regulator 7 and HPF 8.
`
`[0048] The regulator 7 is connected to the cathode of the
`diode 13 in the aforementioned rectification circuit 6 and
`one end of each of the resistor 14 and capacitor 15. The
`regulator 7 stabilizes the electrical signal supplied from the
`rectification circuit 6 by preventing the signal from being
`varied in voltage due to some data component, and supplies
`the signal as a DC power to the sequencer 10. Thus, it is
`possible to suppress a voltage variation caused by a move(cid:173)
`ment of the IC card 1, a voltage variation caused by a change
`of the power consumption inside the IC card 1, etc. If not
`suppressed, such voltage variations will lead to a malfunc(cid:173)
`tion or the like of the sequencer 10.
`
`[0049] The HPF 8 is composed of a capacitor 16 and
`resistor 17. It extracts the high-frequency component from
`the electrical signal supplied from the aforementioned rec(cid:173)
`tification circuit 6, and supplies the signal to the demodu(cid:173)
`lation circuit 9.
`
`[0050] The demodulation circuit 9 is connected to the
`other end of a capacitor 16 of the HPF 8 and one end of the
`resistor 17. It demodulates the high-frequency signal sup(cid:173)
`plied from the HPF 8, and outputs the demodulated signal to
`the sequencer 10.
`
`[0051] The sequencer 10 incorporates a ROM (read-only
`memory) and RAM (random-access memory), and is con(cid:173)
`nected to the aforementioned demodulation circuit 9. The
`sequencer 10 stores a signal ( command) supplied from the
`demodulation circuit 9 as a command into the RAM, ana(cid:173)
`lyzes the command according to a program held in the
`ROM, and reads data from the memory 11 as necessary on
`the basis of the result of analysis or writes data supplied
`from the demodulation circuit 9 into the memory 11. The
`sequencer 10 generates a response signal responsively to the
`command supplied, and supplies the signal to the modula(cid:173)
`tion circuit 12.
`
`[0052] The memory 11 is a non-volatile memory such as
`an EEPROM (electrically erasable programmable read-only
`memory) needing no power for holding data, and connected
`to the aforementioned sequencer 10. The memory 11 stores
`
`data supplied from the demodulation circuit 9 according to
`the result of analysis from the sequencer 10.
`
`[0053] The modulation circuit 12 is formed from a series
`circuit composed of an impedance 18 and an EFT (field
`effect transistor) 19. The impedance 18 is connected at one
`end thereof to the cathode of the diode 13 in the aforemen(cid:173)
`tioned rectification circuit 6, and at the other end to the drain
`of the FET 19. The FET 19 is connected at the source thereof
`connected to the ground potential point, and at the gate to the
`sequencer 10. The modulation circuit 12 is connected in
`parallel to the loop coil 4 included in the aforementioned
`resonant circuit and controls the FET 19 to make a switching
`operation according to a signal supplied from the sequencer
`10 in order to change the load of the impedance 18 to the
`loop coil 4. That is, the modulation circuit 12 adopts the
`so-called additional modulation method.
`
`[0054] The R/W 50 includes a control circuit 51 to control
`data to be sent and received, a modulation circuit 52 to
`modulate the data and the power for operation of the IC card
`1, a demodulation circuit 53 to demodulate received data,
`and a loop antenna 54 that couples with an electromagnetic
`field to send and receive data.
`
`In the R/W 50, the control circuit 51 generates a
`[0055]
`variety of control signals according to an external instruction
`and a program held therein, for example, in order to control
`the modulation circuit 52 and demodulation circuit 53, and
`also generates send data corresponding to an instruction and
`supplies the data to the modulation circuit 52. Also, the
`control circuit 51 generates a reproduce signal according to
`response data from the demodulation circuit 53, and outputs
`the data to outside.
`
`In the modulation circuit 52, a transmitter modu(cid:173)
`[0056]
`lates the send data supplied from the control circuit 51, and
`supplies the modulated signal to the loop antenna 54.
`
`[0057] The demodulation circuit 53 demodulates the
`modulated wave supplied from the loop antenna 54, and
`supplies the demodulated data to the control circuit 51.
`
`[0058] The loop antenna 54 also includes a loop coil
`formed from a plane winding of a conductor. It radiates an
`electromagnetic field corresponding to a modulated wave
`supplied from the modulation circuit 52, and detects a
`variation of the load to the loop coil 4 at the IC card 1. It
`should be noted that the loop antenna 54 has a resonance
`capacitor connected in parallel or in series thereto depending
`upon an antenna driving method adopted in the R/W 50 as
`the case may be.
`
`[0059]
`In the RFID system constructed as above, when the
`IC card 1 is given an instruction for writing a predetermined
`data, the control circuit 51 in the R/W 50 generates a write
`command signal on the basis of the instruction, and also
`generates send data corresponding to the instruction and that
`is to be write data, and supplies the data to the modulation
`circuit 52. The modulation circuit 52 modulates the ampli(cid:173)
`tude of oscillation signal on the basis of the supplied signal,
`and supplies the modulated signal to the loop antenna 54.
`The loop antenna 54 will thus radiate an electromagnetic
`wave corresponding to the supplied modulated signal.
`
`[0060] Note here that the resonant frequency of the reso(cid:173)
`nant circuit composed of the loop coil 4 and capacitor 5
`included in the IC card 1 is set to 13.56 MHz, for example,
`
`Petitioner Samsung and Google
`Ex-1022, 0013
`
`

`

`US 2004/0256468 Al
`
`Dec. 23, 2004
`
`4
`
`as a value corresponding to the oscillation frequency that is
`a carrier frequency from the R/W 50. The oscillation circuit
`receives the radiated electromagnetic field by oscillation,
`converts it into an electrical signal, and then supplies the
`electrical signal to the IC 3. The electrical signal resulted
`from the electromagnetic field is supplied to the rectification
`circuit 6, rectified and smoothed by the rectification circuit
`6 and then supplied to the regulator 7. The regulator 7
`suppresses the voltage variation (data component) of the
`electrical signal supplied from the rectification circuit 6, and
`supplies the electrical signal as a DC power to the sequencer
`10 after the electrical signal is stabilized.
`
`[0061] The signal rectified and smoothed by the rectifica(cid:173)
`tion circuit 6 is supplied to the HPF 8 via the modulation
`circuit 12 where a high-frequency component will be
`extracted from the signal, and then the high-frequency signal
`is supplied to the demodulation circuit 9. The demodulation
`circuit 9 demodulates the supplied high-frequency signal
`and supplies the demodulated signal to the sequencer 10.
`The sequencer 10 stores the signal supplied from the
`demodulation circuit 9 as a command into the RAM, ana(cid:173)
`lyzes the signal according to the program held in the ROM,
`and writes write data supplied from the demodulation circuit
`9 into the memory 11 on the basis of the result of analysis.
`
`[0062] On the other hand, in case the signal supplied from
`the demodulation circuit 9 is a command corresponding to
`the read instruction, the sequencer 10 will read data corre(cid:173)
`sponding to the read instruction from the memory 11. The
`sequencer 10 switches the FET 19 in the modulation circuit
`12 correspondingly to the read data. That is, in the modu(cid:173)
`lation circuit 12, when the FET 19 is turned on, the loop coil
`4 is connected in parallel to the impedance 18. When the
`FET 19 is turned off, the parallel connection between the
`impedance 18 and loop coil 4 is broken. As a result, the
`impedance of the loop antenna 54 at the R/W 50, magneti(cid:173)
`cally connected to the loop antenna 2 at the IC card 1, varies
`correspondingly to the read data. Therefore, the terminal
`potential of the loop antenna 54 will vary correspondingly to
`the impedance variation, and the R/W 50 is thus enabled to
`receive the read data since the variation is demodulated by
`the demodulation circuit 53.
`
`[0063] As above, communications are made between the
`IC card 1 and R/W 50, and the R/W 50 can thus write or read
`data to or from the IC card 1 in a non-contact manner or by
`radio.
`
`[0064] Note here that the aforementioned loop antenna 54
`at the R/W 50 may be an antenna device constructed
`according to the present invention as shown in FIG. 6. The
`antenna device is generally indicated with a reference 60.
`
`[0065] As shown in FIG. 8, the antenna device 60
`includes a loop coil 61 for inductive coupling of an elec(cid:173)
`tromagnetic field, and a magnetic sheet 62 disposed to face
`the main side of the loop coil 61, opposite to the main side
`facing the IC card 1.
`
`[0066] The loop coil 61 is formed by etching or other
`processing of an electroconductive metal foil of electrolytic
`copper or the like formed on both sides of an insulation film
`or substrate 63 made of a flexible film of polyimide or mica.
`It should be noted that the method of forming the loop coil
`61 is not limited to the above one but the loop coil 61 may
`be formed by printing an electroconductive paste such as a
`
`silver paste on the film or substrate 63 to form a conductor
`pattern that provides the loop coil 61 or by sputtering a metal
`target to form, on the substrate 63, a conductor pattern that
`provides the loop coil 61.
`
`[0067] Also, the loop coil 61 is formed asymmetric for the
`winding sections opposite to each other across the center of
`the loop coil 61 to be different in interval and width from
`each other in one direction. That is, the loop coil 61 includes
`an upper winding section 61a larger in interval and width in
`one direction, that is, a vertical direction indicated with an
`arrow Zin FIG. 6, and a lower winding section 61b smaller
`in interval and width in that direction Z.
`
`[0068]
`In this case, the magnetic field distribution in the
`antenna device 60 is asymmetric and enhanced at the upper
`winding section 61b of the loop coil 61 where the winding
`interval and width are large in the Z-directional plane
`through the center of the loop coil 61 perpendicular to the
`long side of the rectangular antenna and X-directional plane
`though the center perpendicular to the short side as shown in
`FIGS. 7A to 7C. Namely, the magnetic field distribution in
`the antenna device 60 is different from the symmetric
`magnetic field around the loop coil 200 shown in FIG. 1.
`
`In the antenna device 60 according to the present
`[0069]
`invention, the loop coil 61 is formed asymmetric and the
`distribution of a magnetic field radiated from the loop coil 61
`is controlled, whereby the aforementioned range of commu(cid:173)
`nications between the IC card 1 and R/W 50 can be widened
`and the position of communications can be done can be
`shifted in one direction.
`
`[0070] As in FIG. 7B, the winding interval at a side of the
`loop coil, indicated with a reference Zl, is larger than the
`conventional one while the winding interval at a side of the
`loop coil, indicated with a reference Z2, is generally equal
`to the conventional one. That is, the magnetic field will be
`distributed more widely at the side Zl than that at the side
`Z2. The magnetic field about a point Pl will be weaker than
`that about a point P2, the points Pl and P2 being positioned
`at the sides Zl and Z2, respectively, and equidistant from an
`origin that is an intersection between the Z and H axes, and
`the magnetic field will spread in a wide range while the
`magnetic field density is totally low at the point Pl. Thus,
`the position of communications will be shifted.
`
`[0071] Note that the magnetic field distribution at the side
`Z2 where the winding interval is generally the same as the
`conventional one is nearly the same as that attained when the
`winding interval is uniform over the conventional loop
`antenna.
`
`[0072] Since the loop coil 61 can be formed smaller than
`the loop coil 4 at the IC card 1, the antenna device 60 can
`be formed even smaller.
`
`[0073] Note that the antenna device 60 according to the
`present invention is not limited to any antenna device in
`which one winding section of the loop coil 61 is different in
`both winding interval and width from the other winding
`section opposite to the one winding section as shown in
`FIGS. 7 A to 7C but the antenna sections of the loop coil 61
`may be different in interval alone from each other as shown
`in FIG. 8 for example.
`
`[0074] Also, the loop coil 61 is formed asymmetric in the
`aforementioned one direction, but it may be formed asym-
`
`Petitioner Samsung and Google
`Ex-1022, 0014
`
`

`

`US 2004/0256468 Al
`
`Dec. 23, 2004
`
`5
`
`metric in an arbitrary direction in which it is desired to
`widen the distribution of radiated magnetic field. For
`example, the loop coil 61 may be formed asymmetric for the
`winding sections thereof to be different in winding interval
`and width from each other in the direction of arrow X
`perpendicular to the aforementioned direction of arrow Z, as
`shown in FIGS. 9 and 10. Alternatively, the loop coil 61
`may be formed asymmetric for the winding sections thereof
`to be different in winding interval and width from each other
`in both the directions of arrows Z and X.
`
`[0075] Note that the loop coil 61 shown in FIG. 9
`includes, in the direction of arrow Z, the upper winding
`section 61a where the windings are smaller in interval and
`width and lower winding section 61b where the windings are
`larger in interval and width, and in the direction of arrow X,
`a left winding section 61c where the windings are smaller in
`interval and width and a right winding section 61d where the
`windings are larger in interval and width. On the other hand,
`the loop coil 61 shown